The present invention is in the building construction field and particularly relates to windows and doors, especially metal windows and doors employing insulated glass panels. The invention is applicable to single or double hung windows and to vertically or horizontally sliding or rolling windows or doors.
The invention particularly relates to thermally insulated windows or doors and similar panel assemblies for installation in a rough opening of an enclosing wall exposed to different temperature conditions at the opposite sides thereof.
The relatively high thermal conductivity of metals, such as aluminum, is probably the most undesirable property limiting their substitution for wood and other less conductive non-metallic structural materials. The effect of this metal characteristic is best seen in windows or doors or other panel assemblies employing metal framing in direct conductive relationship with air at interior and exterior ambient temperatures giving rise to the generation and presence of frost and moisture condensation on the interior surfaces of the framing, especially in northern climates where extreme temperature differentials prevail. When a panel assembly has a metal outer frame fixed in the rough opening of a wall and a sash or sashes movably mounted in such fixed outer frame and each having a metal frame peripherally embracing a glass or other panel, the thermal conductivity problem exists with respect to the metal sash frame as well as the metal outer or fixed frame.
A wide variety of solutions to overcome the deleterious high thermal conductivity of metal framing for windows and doors and similar panels have been proposed with varying degrees of success. Most of these have included some type of thermal break or insulating material installed in an appropriate part of the metal frame. Some of these thermal break or thermal barrier concepts have been relatively simple while others have been somewhat complex. Examples of thermal barrier window or door constructions may be found in U.S. Pat. Reissue Nos. 24,704; 3,055,468; 3,289,377; 3,302,354; 3,332,184; 3,393,487; 3,411,254; 3,462,884; 3,487,580; 3,600,857; and 3,780,473.
It is a primary object of the present invention to provide a metal thermal break or thermal barrier window or door or like construction having vertically or horizontally sliding or rolling panels wherein all metal framing members including header, jambs, sill, rails and stiles thereof are exposed either completely to interior or exterior temperatures.
Another object of the invention is to provide a thermal break panel assembly wherein no additional thermal insulation is required for sash rails or sash stiles.
Still another object of the invention is to provide a thermally insulated window, door or the like, which is structurally sound, simple of design and which can be economically manufactured.
Other objects and advantages of the instant invention will become apparent from a consideration of the descriptions and drawings hereinafter.